to kill hydra

You need to stand in front of the platform and keep nailing it with your blades ...

You need to stand in front of the platform and keep nailing it with your blades of chaos.
The best time to do this is just after its tried to bite you and its close to the
platform. When it comes in to bite you, use the lightning to hurt it. If it screams, block
and you wont fall off the platform.
Keep doing this until you get the O over its head (4 times I think) and you can finish it